Empathy definitely has to be exercised and trained regularly to work well. As I understand it (not an expert but I've read up on it on the Internet), children a

Empathy definitely has to be exercised and trained regularly to work well. As I understand it (not an expert but I've read up on it on the Internet), children are pretty much incapable of it until ~4 as there's some mental development necessary. If you spend lots of time in an environment where you're not conscious of building your empathy and remembering to use it, your ability and tendency to do so will wither.